The well known drain auger or plumber's snake is a long, slender, springy device that is run lengthwise into a drain duct to break up a collection of solid or clotted material that is blocking flow through the drain. Usually such an auger consists of a single length of spring wire wound into small, uniform-diameter, closely spaced coils, and it is stiff enough to be pushed lengthwise into a drain duct but resilient enough to follow the curves in the duct. If the duct is fairly straight or has only gradual curves, the auger will usually move along it nicely, but because of its stiffness it resists following a sharp curve.
Even greater difficulty has heretofore arisen when the front end of a drain auger arrived at a junction of two ducts at some distance from a drain inlet, because there was no way to guide the auger into a selected one of the branches. Usually the front end of the auger could not be seen when it arrived at such a junction, and therefore even if the plan of the drain system was well known to the person using the auger, entry of the auger into the desired branch was more a matter of luck than of skill. Clearing a drain blockage is never enjoyable, but in such a situation the task could be frustrating, aggravating and time-consuming as well as lacking in esthetic appeal.
Maintenance personnel who are responsible for plumbing systems in commercial, industrial and office buildings are familiar with another problem that has often resulted from the inability to control a drain auger into a selected one of two or more branches in a drain system. Where several plumbing fixtures such as toilets or wash basins are connected to a common soil pipe a drain auger run into the drain system at any one location was likely to come out into one of the fixtures if it followed the wrong branch duct. Often the auger emerged into a fixture in another room, so that the user of the auger had no way of knowing that it was not only failing to accomplish its purpose but was possibly marring and chipping the fixture against which its leading end was whipping and banging.
Heretofore there has been no obvious solution to this problem. Several devices have been proposed whereby a cable or the like can be guided along a narrow, duct-like passage, as in U.S. Pat. No. 2,286,781 to Abramson et al and U.S. Pat. No. 2,727,721 to Pinkerton, but with these the cable was guided at an end at which it was being pulled.
U.S. Pat. No. 2,410,753, to Shinomiya, disclosed a device for drilling deep wells comprising a flexible sheath that had a drill bit projecting from its free lower end. A cable that extended along the sheath and slid in connections to the sheath at intervals along its length could be tensioned to curve the lower end portion of the sheath, but the sheath could only be curved towards its side along which the cable extended, and if the sheath had the flexibility of a drain auger, it would have been hard to position in rotation and would have afforded little or no control.
U.S. Pat. No. 2,973,537 to Simpson disclosed a drain auger guide which was essentially an adaptation of the principles of the drill guide of the Shinomiya patent.
U.S. Pat. No. 2,887,703 to Williams disclosed a drain auger guide that comprises a rigid tube with a flexible sheath projecting lengthwise from its front end. The auger proper extended through the tube and the sheath and forwardly beyond the sheath. A chain was connected between a ring that was relatively fixed on the rigid tube and another ring which could be locked to the sheath at any position along its length and which could be so adjusted along the sheath as to establish tension in the chain at the value needed for a desired curvature of the sheath. However, the device had to be adjusted when it was outside of the drain to be cleaned, and the user had to estimate the amount of curvature that would be needed for causing the auger to follow a critical part of the drain. This was impractical, because it is often impossible to know which way a drain curves at a distance from an inlet to it.
Other prior U.S. patents that are more or less pertinent to the general problem here under consideration are: No. 2,718,376, to Raney, which disclosed a device whereby a flexible probe could be guided into a conduit but which afforded no guidance to the part of the probe that was in the conduit; No. 3,623,701, to Dudley, which disclosed means for guiding a rope around a pulley of known radius; No. 1,261,444, to Schied, which disclosed a drain auger per se and evidenced no recognition of the problem here under consideration; and No. 1,219,049, to Sticklin, which related to a sprayer duct having an outlet end portion that could be curved to a desired radius by means of a "pull member" generally embodying the principle employed in the above discussed Shinomiya patent.
From this brief review of the state of the pertinent art, it will be apparent that the very common and extremely annoying problem to which the present invention is directed has persisted because there has heretofore been no obvious solution to it.